As soon as the originator of an e-mail message “sends” it, the message is fixed. Often it is saved, at least temporarily, on the originators hard drive and on the receiver’s hard-drive.

The author of an e-mail message is the owner of the copyright for that message, unless it is created by the author as part of his job, in which case it would be owned by the employer.

This means, of course, that forwarding an e-mail message without the permission of the author may be copyright infringement, unless this use constitutes a fair use or the owner of the message has given permission. However, it’s not likely that anyone would bring a copyright suit over anything so valueless as e-mail.

Source:  page 14/9 Fishman, Stephen (attorney) The Copyright Handbook - How to Protect and Use Written Works, Nolo.com Feb 2000